Impact of the Contour Conditions of Achromatic Patterns Using Watercolor Effects on Perceived Brightness

Abstract

  It has been reported that the whiteness of the area surrounded by the 2 chromatic lines which mediate watercolor effect can be enhance by choosing certain conditions such as color and luminance. In this study, we conducted a pairwise comparison experiment using the achromatic stimuli which arose watercolor effect. They were composed of the combination of two lines of different levels of gray. The stimuli were presented on the gray background and two levels of gray were selected from five luminance values. The brightness inside the inner contour lines was evaluated to examine their impact on the perception of brightness and related factors. The results revealed that the 10 subjects, who served as observers, could be broadly divided into two types. It was also found that the perception of brightness could be enhanced by the stimuli produced by achromatic watercolor effects. The suggested factors were the relationship of the total inner and outer contour lines with the luminance value, and the relationship of inner and outer contour lines with the difference in background brightness.